/Engine/Source/Runtime/Landscape/Public/LandscapeEdit.h
Heightmap access
void SetHeightData ( int32 X1, int32 Y1, int32 X2, int32 Y2, const uint16 * InData, int32 InStride, bool InCalcNormals, const uint16 * InNormalData, const uint16 * InHeightAlphaBlendData, const uint8 * InHeightRaiseLowerData, bool InCreateComponents, [UTexture2D](API\Runtime\Engine\Engine\UTexture2D) * InHeightmap, [UTexture2D](API\Runtime\Engine\Engine\UTexture2D) * InXYOffsetmapTexture, bool InUpdateBounds, bool InUpdateCollision, bool InGenerateMips )